kill the goose that lays the golden eggs字面意思杀掉下金蛋的，真实含义是杀鸡取卵；竭泽而渔；断绝财路。

【例句】
They regularly buy large quantities from us, so we should not put up our prices too much; we don't want to kill the goose that lays the golden eggs.
他们定期向我们大量购买，因此我们不应该把价格抬得太高，我们不想杀鸡取卵。

They sold part of their business but it was the most profitable part. I think that they have killed the goose that lays the golden eggs.
他们把一部分生意转手了，但这部分利润最大。我想他们是杀鸡取卵。